PRODUCT INFORMATION
PROCESS ANALYSIS
AMPEROMETRIC SENSORS
Smart amperometric free chlorine,
chlorine dioxide and ozone sensors
➔ Stable measuring results
thanks to flow optimisation
➔ Premounted flow cell,
easy to install
➔ Special accessories for
optimal operation
➔ Compatible with
multi-parameter digital
SC controllers
➔ Minimal maintenance with
automatic cleaning
Simple installation and operation
The all-inclusive systems come preassembled on a panel. Just mount the
panel in the desired location, install the
sensors, and connect the controller to
get started. There are no chemicals
used for measurement. Membranes
are premounted on retaining caps so
the maintenance and the operational
costs are minimal. Two years of typical
maintenance items are included with
the system.
Options for optimised operation
For all amperometric sensors several
accessories are available:
➔ Acidification unit
This can be used for sample pH
adjustment or for cleaning. It is fully
programmable.
➔ Intermittent flow unit
This free programmable unit reduces
the amount of sample water which is
sent to waste.
PROCESS ANALYSIS_AMPEROMETRIC SENSORS
Free chlorine
Low detection limit for efficient
residual chlorine monitoring
The 9184 sc amperometric free chlorine sensor has a detection limit of
5 ppb or 0.005 mg/l hypochlorous acid
(HOCl). Together with pH and temperature measurements, free chlorine concentration is calculated using dissociation curves stored in the instrument.
Wide measurement range
Due to its 0 to 20 ppm measurement
range, the 9184 sc free chlorine sensor is particularly useful for drinking
water distribution monitoring, chlorination applications, demineraliser systems or cooling water processes.
Three forms of chlorine
Measurements are made continuously
by the sensor and reported to the
controller.
Depending on model, the
9184 sc sensor can measure:
➔ Hypochlorous acid
(HOCl) only
➔ HOCl via acidification
➔ Total free chlorine (TFC) by
measuring temperature and pH
together with HOCl to calculate
hypochlorite ions (OCl–). HOCl
combined with OCl– equals total
free chlorine.
Fig. 1: Dissociation curve
Active chlorine operations
Active chlorine (HOCl) or hypochlorous
acid is a powerful disinfectant – up to
100 times more efficient than
hypochlorite ions.
➔ Total free chlorine (TFC) is composed of dissolved chlorine (at low pH
values), hypochlorous acid gas, and
hypochlorite ion (ClO–) coexisting in
the sample.
Their relative proportion depends on
pH and temperature (see figure 1
above).
➔ Total combined chlorine (TCC)
results from the addition of total free
chlorine and chloramines (mono-, diand tri-chloramines).*
* 9184 sc does not measure TCC.
Ozone
Wide measurement range with
few interferences
Bromine, chloramines, chlorine, chlorine dioxide, hydrogen peroxide, and
pH do not interfere with ozone measurements when using the 9185 sc
amperometric ozone sensor which can
measure from 0 to 2 mg/l ozone.
Ideal for low conductivity
samples
The 9185 sc ozone system has a low
minimum detection limit of 0.005 mg/l
ozone. And because the amperometric
cell is separated from the sample by
the membrane and is immerged into
an electrolytic medium, the
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9185 sc ozone sensor is suitable
for use in water with low
conductivity.
Ozone operations
Ozone is highly soluble in water –
up to 13 times more soluble than
oxygen. Ozone is also highly
unstable in water with stability
decreasing with increasing
temperature.
Ozone reacts with hydroxide ions
(OH–). As the concentration of OH–
increases (pH increases), reaction with
ozone increases (see figure 2). The
hydroxide ion OH– is a by-product of
Fig. 2: Time of breakdown (mn) of dissolved ozone
ozone breakdown in water and the
reaction between OH– and O3 can be
sustained until ozone is completely
removed.
PROCESS ANALYSIS_AMPEROMETRIC SENSORS
Chlorine dioxide
Selective membrane avoids interference from chlorine
The 9187 sc amperometric chlorine
dioxide sensor uses a membrane that
is selective for chlorine dioxide molecules. There are no interferences from
bromine, chlorine, or hydrogen
peroxide.
The only potential interference is
from ozone, which is rarely present in
water treated with chlorine dioxide.
The oxidation potential of chlorine
dioxide is 2.5 times higher than chlorine. It is relatively independent from
the pH value and therefore suitable for
disinfection of alkaline water.
The electrochemical reaction and diffusion through the membrane are temperature dependent. The measurement
cell contains a temperature sensor for
automatic temperature compensation
to prevent measurement errors.
The sensor should be installed in an accessible location. It can be mounted on a flat, vertical surface (such as a panel, stand, etc.). It should allow for
access for any checking or maintenance. Sample flow should meet the specifications on the last page.
Note: The optional pH probe is used for the 9184 sc free chlorine TFC sensor only.
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PROCESS ANALYSIS_AMPEROMETRIC SENSORS
Technical data
PARAMETER
Measurement range
Minimum detection limit
Accuracy
Response time
Measurement interval
Minimum flow rate
Pressure range
Sample temperature
Temperature compensation
Sample pH
Measurement technology
Interferences
Mounting
Connections
Materials
Controller
Environmental ratings
Dimensions
9184 sc - FREE CHLORINE
0 to 20 ppm (mg/l) as HOCI
5 ppb or 0.005 mg/l HOCl
2% or ±10 ppb HOCl,
whichever is greater
9185 sc - OZONE
9187 sc - CHLORINE DIOXIDE
0 to 2 ppm (mg/l) O3
0 to 2 ppm (mg/l) as ClO2
5 ppb or 0.005 mg/l O3
10 ppb or 0.01 mg/l ClO2
3% or ±10 ppb O3,
5% or ±10 ppb ClO2,
whichever is greater
whichever is greater
90% in less than 90 seconds
Continuous
14 l/h (200 to 250 ml/min) auto-regulated by flow through cell
0.1 to 2 bar in flow cell
2 °C to 45 °C
Automatic over sample temperature range
4 to 8 (acidification unit available for
–
–
pH greater than 8)
Amperometric/membrane
No interference from chloramines,
No interference from bromine,
Ozone
chlorine dioxide and ozone interfere chloramines, chlorine, chlorine dioxide,
with measurement
or hydrogen peroxide
Flat, vertical surface (panel, stand, etc.)
Sample line: 1/4 inch O.D., drain line: 1/2 inch I.D. (supplied)
Electrode: gold cathode/silver anode, measuring cell: acrylic, probe body: PVC
SC 100 / SC 1000
Integrated
IP 66/NEMA 4X
299 x 250 mm (11.77 x 9.84 inch)
Subject to change without notice.
Ordering information
* Required when the length of cable between the digital sensor and
SC 100 or SC 1000 controller exceeds 100 m.
HACH LANGE Services
On-site support by our technical
field staff.
Quality assurance, complete with
standard solutions, instrument
checks and test solutions.
www.hach-lange.com –
up to date and secure, with
downloads, information and shop.
DOC063.52.00441.Jun07
DESCRIPTION
ART. NO.
9184 sc free chlorine HOCl sensor
LXV430.99.00001
9184 sc free chlorine TFC sensor
LXV432.99.00001
9185 sc ozone sensor
LXV433.99.00001
9187 sc chlorine dioxide sensor
LXV434.99.00001
ACCESSORIES
Digital extention cable 1 m (other lenghts available) 61224-00
Digital termination box*
58670-00
9180 sc acidification unit
LZY051
9180 sc intermittent flow unit
LZY052
REPLACEMENT PARTS
pH electrode
Z368416,00000
9184 sc electrode
Z09184=A=1001
- Premounted membranes, qty. 4
Z09184=A=3500
- Electrolyte
Z09184=A=3600
9185 sc electrode
Z09185=A=1000
- Premounted membranes, qty. 4
Z09185=A=3500
- Electrolyte
Z09185=A=3600
9187 sc electrode
Z09184=A=1001
- Premounted membranes, qty. 4
Z09187=A=3500
- Electrolyte
Z09187=A=3600